Species reintroduction
However, reintroduction of a species can also be for pest control; for example, wolves being reintroduced to a wild area to curb an overpopulation of deer.
Because reintroduction may involve returning native species to localities where they had been extirpated, some prefer the term "reestablishment".
In situ sourcing for restorations involves moving individuals from an existing wild population to a new site where the species was formerly extirpated.
Living collections are more costly than storing germplasm and hence can support only a fraction of the individuals that ex situ sourcing can.
Thus, efforts should be made to replicate wild conditions and minimize time spent in captivity whenever possible.
[13] 184 case studies were reported on a range of species which included invertebrates, fish, amphibians, reptiles, birds, mammals, and plants.
A similar assessment focused solely on plants found high rates of success for rare species reintroductions.
Predators, food, pathogens, competitors, and weather can all affect a reintroduced population's ability to grow, survive, and reproduce.
The number of animals reintroduced in an attempt should also vary with factors such as social behavior, expected rates of predation, and density in the wild.
[20] They state that restoration of the original habitat and amelioration of causes of extinction must be explored and considered as essential conditions for these projects.
[2] Reintroduced populations experience increased vulnerability to influences of drift, selection, and gene flow evolutionary processes due to their small sizes, climatic and ecological differences between source and native habitats, and presence of other mating-compatible populations.
Plants or animals that undergo reintroduction may exhibit reduced fitness if they are not sufficiently adapted to local environmental conditions.
Therefore, researchers should consider ecological and environmental similarity of source and recipient sites when selecting populations for reintroduction.
[27] Conservation agencies have developed seed transfer zones that serve as guidelines for how far plant material can be transported before it will perform poorly.
The genetic basis of this adaptation is selection of rare, recessive alleles that are deleterious in the wild but preferred in captivity.
[31] Extent of adaptation is directly related to intensity of selection, genetic diversity, effective population size and number of generations in captivity.
Characteristics selected for in captivity are overwhelmingly disadvantageous in the wild, so such adaptations can lead to reduced fitness following reintroduction.
For both preparation and monitoring of reintroductions, increasing contacts between academic population biologists and wildlife managers is encouraged within the Survival Species Commission and the IUCN.
The IUCN states that a re-introduction requires a multidisciplinary approach involving a team of persons drawn from a variety of backgrounds.
[21] A survey by Wolf et al. in 1998 indicated that 64% of reintroduction projects have used subjective opinion to assess habitat quality.
[21] Population dynamics models that integrate demographic parameters and behavioral data recorded in the field can lead to simulations and tests of a priori hypotheses.
It does this by actively developing and promoting sound inter-disciplinary scientific information, policy, and practice to establish viable wild populations in their natural habitats.
